Rock-drill valve



' Aug. 24, 1926.

- k 1,597,394 F. M. SLATER ROCK DRILL VALVE Filed Sept. 16, 1925 I INVENTOR my ATRNEY- Y Patented Aug. 24, 1926.

UNITED STATES PATENT oFFicE.

FRED M. sLArRR, or EASTON, PENNSYLVANIA, ASSIGNOR TO INGERSOLL-RANZD COM- PANY, or JERSEY CITY, NEW JERSEY, A CORPORATION or NEW JERSEY.

BOCK-V-DRILL VALVE.

Application filed September 16, 1925." Serial NO.'56,680;

This invention relates to rock drills, but more particularly to a spool valve controlling both the inlet and exhaust of the cylinder.

The objects of the invention are to enable the valve to bethrown or actuated in one direction or the other by pressure fluid under working pressure, and held after being thrown by live air pressure direct from the main supply.

Further objects of the invention will hereinafter appear and the invention is shown in one of itspreferred forms in the accompanying drawings, in which- Figures 1 .an d2 are diagrammatic longitudinal sectional elevations partly broken away of so much of a rock drill as will serve to illustrate the invention, showing the valve and piston in two difierent positions.

Referring to the drawings, the cylinder A is provided with the reciprocating piston B and the distributing valve C reciprocates in the valve chest D. Live air is supplied at the main supply port E which is controlled by the central head F of the valve. The exhaust ports G and H in the valve chest are controlled by the end heads J and K of the valve. These heads, as shown in this instance, are all of the same diameter which is the preferable construction. The valve chest is closed by the valve bushings L which also form valve stops.

Combined inlet and exhaust passages O:

and P lead from the central portion of the valve chest to the ends of the cylinder and crossed kicker ports Q and R lead from the central portion of the cylinder to the end spaces S and T of the valve chest to enable the valve tobe actuated in one direction or the other by pressure fluid under working pressure.

Means areprovided for constantly permitting leakage of live air through-a port or ports U in the central head F and through passages V in the valve body leading to the end spaces S and T of the valve chest toenable the valve to be held in one position or the other by live air. A convenient construction is that shown in the drawings in which the central head F is provided with the groove W so that the live air leak port U is always open to the supply through the main port E. r

The end heads J and K are provided with the leak-ports X leading tothe end spaces S and Tin the valve chest, and these leak ports X are adapted tobe alternately out 01f or else placed in communication with their respective exhaust ports G and H so that when pressure ,fluid'is holding the valve in one direction dueto leakage into the space at that end of the valve while the ports X are cut off, the space in the chest at the opposite end of the valve is open to atmosphere through the leak ports X.

In the operation of the device, let it beassumed that the piston B is travelling forwardly as indicated in Figure 1 in'which case the valve C will be in forward position and pressure fluid is supplied from the main port E around the valve and through the passage 0 to the rearward end of the cylinder. The forward end of the cylinder exhausts through the passage P around the valve to the exhaust port G. Since the leak ports X in the valve head K are cut off, the leakage of pressure fluid through the central head F and the valve body to the space T at the end of the valve chest enables sufl'icient pressure to be built up to hold the valvein the desired position. Some leakage to atmosphere mayoccur through the picker port It and thence through the cylinder and passage P to the exhaust G but not sufiicient to prevent the valve to be securely held for the desired instant of time. This is due to the fact that the kicker port Riis of smaller cross sectional area than the'combined areas of the leak ports X in the end head J. y

As the piston B travels forward and uncovers the kicker port Q, pressure fluid under working pressure is supplied to the space S in the valve chest, and since the ports X are small the valve is quickly thrown to the position indicated ii n Figure 2, thus cutting ofi the leak ports X in the end head J and enabling the pressure fluid leaking into the forward passage B to hold the valve in the position indicated in Figure 2 while the piston is travelling rearwardly.

When the piston uncovers the kicker port R in its rearward travel, the pressure fluid passageV holds the valve in forward position as indicated in Figure 1. From thispoint the cycle is repeated.

I claim: v v 1. In a fluid actuated rock drill, the combination of a cylinder and reciprocating pis ton, a valve chest having'exhaust ports, a reciprocating distributing valve in said chest, cylinder inlet and exhaust passages leading from the chest to the cylinder andwon: trolled by the valve, said valve having a central head. and end-heads, means. for constantly permitting. liveair to leak throughthe central head and: the valve body. to the spaces at both ends; of the valve chest, leak. ports in the. end heads adapted tor'alternatellyconnect' the said end spaces With their: respective: exhaust ports and to heal ternately cut efii as the valve reciprocatesm whereby the valves is held in one position: or the other; by live airafter being throav'n, and

kicker ports connecting: the said end spacesoi the valve chest With the cylinder and controlled. by the. piston for actuating: the

valve by pressure finidi under working pres- 2; In a fluid actuated rock drill, the combination of a cylinder and reciprocating piston, a valve chest, a reciprocating. spool valve in said chest having a central head and end heads, of the same diameter, a main supplyport in the chest controlled by the central head, exhaust ports in the chest con-- troli-ed by the end heads, combined inlet and exhaust passages leading to the ends of the cylinder, kickerports leading from the cylinder to the end spaces of the valve chest, a port in -Vthe central-head in constant comniuni'cati on with a the main s n-pp lyportand communicating through passages in: the;

valve body for admitting pressure fluid to,

the end spaces in the chest to hold the valve in throw position, and leak-ports inthe end heads leading to said end spaces and FRED SLATER; 

